The candidate, Laura Carbone M.D., is a new investigator in the field of metabolic bone diseases. Immediate goals include acquiring expertise in study design. This will be provided on a ongoing basis by the co-mentors Dr. Genaro Palmieri, a well known expert in metabolic bone disease, and Dr. William B. Applegate, an expert in large multi-center clinical trials. Long term goals include obtaining the skills necessary to do clinical trials in metabolic bone diseases. This will be provided at this center by weekly classes in statistics and epidemiology, seminars in nutrition and osteoporosis and a program leading to a master of science degree in epidemiology. The specific research plan is detailed below: Racial differences in bone metabolism, bone mineral density and fracture rates have been reported between Caucasians and African Americans with Caucasians generally having increased biochemical markers of bone metabolism, decreased bone mineral density and higher fracture rats than African Americans. More recent data, however, suggests that the incidence of osteoporosis and osteoporotic fractures may be increasing in African Americans. Environmental factors, specifically salt intake, have been shown to influence bone metabolism in Caucasians, but have not been studied in African Americans, despite the fact that the African American diet may be high in sodium. This study proposes to examine the effects of sodium load and then a sodium restriction diet of calciotropic hormones and biochemical markers of bone metabolism in African American and Caucasian women.